A patient has been diagnosed with pulmonary hypertension, in which the capillaries in the alveoli are squeezed excessively. The nurse should recognize a disturbance in what aspect of normal respiratory function?

Correct Answer: B

Rationale: The correct answer is B: Perfusion. Pulmonary hypertension affects blood flow through the lungs, leading to decreased perfusion. This results in inadequate oxygenation of the blood. Acid-base balance (A) is maintained by the kidneys and lungs, not directly impacted by pulmonary hypertension. Diffusion (C) refers to gas exchange in the alveoli, which is affected by perfusion but not the primary disturbance in pulmonary hypertension. Ventilation (D) is the process of moving air in and out of the lungs, which is not primarily affected by pulmonary hypertension; it is more related to conditions like COPD.

Correct Answer: B

Rationale: The correct answer is B (45 mm Hg) because the partial pressure of carbon dioxide in venous blood is typically around 40-45 mm Hg. This value represents the amount of CO2 dissolved in the blood plasma. Option A (40 mm Hg) is slightly on the lower side and may not fully reflect the average value. Option C (50 mm Hg) is higher than the usual range for venous blood CO2 levels. Option D (70 mm Hg) is significantly higher than the normal range and is more characteristic of arterial blood CO2 levels. Therefore, option B is the most accurate representation of the partial pressure of CO2 in venous blood.

Correct Answer: C

Rationale: The correct answer is C: electrolyte balance. Hemoglobin's affinity for oxygen is primarily influenced by factors such as pH, temperature, and the partial pressure of oxygen (PO2). Electrolyte balance, on the other hand, does not directly impact hemoglobin's ability to bind with oxygen. Changes in electrolyte levels may affect overall blood composition but do not directly alter hemoglobin's oxygen-binding capacity. Therefore, electrolyte balance does not affect hemoglobin's affinity for oxygen, making it the correct choice. RBC metabolic activity can impact oxygen release from hemoglobin, temperature can affect hemoglobin's oxygen-binding capacity, and the PO2 of blood directly influences oxygen binding to hemoglobin.

Correct Answer: C

Rationale: Emphysema is the correct answer because it is characterized by the destruction of alveolar walls and connective tissues in the lungs, leading to reduced respiratory surface area. Asthma is characterized by airway inflammation and bronchoconstriction. Bronchitis is inflammation of the bronchial tubes. Tuberculosis is a bacterial infection affecting the lungs. Emphysema best fits the description provided in the question.

Correct Answer: C

Rationale: The correct answer is C: Smoking. Smoking is a risk factor for developing heart failure because it damages the blood vessels, increases blood pressure, and reduces oxygen delivery to the heart. Regular exercise (A) is actually beneficial for heart health. Low blood cholesterol levels (B) are generally considered a positive factor for heart health. Adequate sleep (D) is important for overall well-being but is not a direct risk factor for heart failure. In conclusion, smoking (C) stands out as the correct answer due to its harmful effects on the cardiovascular system.